smtp.mailidea.net has no CNAME records.
Question and response
Question
dig smtp.mailidea.net. NS
Answer
The response has no answer records.
Authority
mailidea.net. 300 SOA x.ns.joker.com. hostmaster.joker.com. 2024110768 14400 3600 1209600 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0